<template>
    <div class="box1">
        <div
            class="darg"
            ref="customerService"
            @touchmove="touchmoveHandle('customerService', $event)"
            @touchstart="touchstartHandle('customerService', $event)"
            @click="$router.push('/liuyan')"
        >
            <span class="icon iconfont">&#xe61b;</span>
        </div>
    </div>
</template>

<script>
export default {
  name: "myDarg",
  data() {
    return {
      touch: {
        initialPosition: {},
        movePostion: {}
      },
      element: {
        initialPosition: {},
        movePostion: {}
      }
    };
  },
  methods: {
    touchstartHandle(refName, e) {
      // console.log(e)
      // 触摸开始
      let touchTarget = e.targetTouches[0];
      // 记录触摸点的坐标（初始位置）
      this.touch.initialPosition = {
        x: touchTarget.clientX,
        y: touchTarget.clientY
      };
      // 记录需要移动的元素坐标（初始位置）
      this.element.initialPosition = {
        x: this.$refs[refName].offsetLeft,
        y: this.$refs[refName].offsetTop
      };
    },
    touchmoveHandle(refName, e) {
      e.preventDefault();
      let touchTarget = e.targetTouches[0];
      // 根据初始touch位置计算移动距离:元素移动位置=元素初始位置+(光标移动后的位置-光标点击时的初始位置)
      let X =
        this.element.initialPosition.x +
        (touchTarget.clientX - this.touch.initialPosition.x);
      let Y =
        this.element.initialPosition.y +
        (touchTarget.clientY - this.touch.initialPosition.y);
      // 限制可移动距离，不超出可视区域
      let maxWidth = innerWidth - this.$refs[refName].offsetWidth;
      let maxHeight = innerHeight - this.$refs[refName].offsetHeight;
      X = X <= 0 ? 0 : X >= maxWidth ? maxWidth : X;
      Y = Y <= 0 ? 0 : Y >= maxHeight ? maxHeight : Y;
      // console.log(X,Y)

      // 移动元素
      this.$refs[refName].style.left = X + "px";
      this.$refs[refName].style.top = Y + "px";
    }
  }
};
</script>

<style lang="scss" scoped>
.darg {
  width: 100px;
  height: 100px;
  background-color: #007aff;
  border-radius: 50%;
  color: #ffff;
  text-align: center;
  line-height: 100px;
  // font-size:60px;
  position: fixed;
  bottom: 400px;
  right: 0;

  i {
    font-size: 60px;
  }
}
</style>
